Jan Stephan Sanders

Genetically Distinct Subsets within ANCA-Associated Vasculitis

BACKGROUND Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a severe condition encompassing two major syndromes: granulomatosis with polyangiitis (formerly known as Wegeners granulomatosis) and microscopic polyangiitis. Its cause is unknown, and there is debate about whether it is a single disease entity and what role ANCA plays in its pathogenesis. We investigated its genetic basis. METHODS A genomewide association study was performed in a discovery cohort of 1233 U.K. patients with ANCA-associated vasculitis and 5884 controls and was replicated in 1454 Northern European case patients and 1666 controls. Quality control, population stratification, and statistical analyses were performed according to standard criteria. RESULTS We found both major-histocompatibility-complex (MHC) and non-MHC associations with ANCA-associated vasculitis and also that granulomatosis with polyangiitis and microscopic polyangiitis were genetically distinct. The strongest genetic associations were with the antigenic specificity of ANCA, not with the clinical syndrome. Anti-proteinase 3 ANCA was associated with HLA-DP and the genes encoding α(1)-antitrypsin (SERPINA1) and proteinase 3 (PRTN3) (P=6.2×10(-89), P=5.6×10(-12,) and P=2.6×10(-7), respectively). Anti-myeloperoxidase ANCA was associated with HLA-DQ (P=2.1×10(-8)). CONCLUSIONS This study confirms that the pathogenesis of ANCA-associated vasculitis has a genetic component, shows genetic distinctions between granulomatosis with polyangiitis and microscopic polyangiitis that are associated with ANCA specificity, and suggests that the response against the autoantigen proteinase 3 is a central pathogenic feature of proteinase 3 ANCA-associated vasculitis. These data provide preliminary support for the concept that proteinase 3 ANCA-associated vasculitis and myeloperoxidase ANCA-associated vasculitis are distinct autoimmune syndromes. (Funded by the British Heart Foundation and others.).

Ciliopathies with Skeletal Anomalies and Renal Insufficiency due to Mutations in the IFT-A Gene WDR19

A subset of ciliopathies, including Sensenbrenner, Jeune, and short-rib polydactyly syndromes are characterized by skeletal anomalies accompanied by multiorgan defects such as chronic renal failure and retinitis pigmentosa. Through exome sequencing we identified compound heterozygous mutations in WDR19 in a Norwegian family with Sensenbrenner syndrome. In a Dutch family with the clinically overlapping Jeune syndrome, a homozygous missense mutation in the same gene was found. Both families displayed a nephronophthisis-like nephropathy. Independently, we also identified compound heterozygous WDR19 mutations by exome sequencing in a Moroccan family with isolated nephronophthisis. WDR19 encodes IFT144, a member of the intraflagellar transport (IFT) complex A that drives retrograde ciliary transport. We show that IFT144 is absent from the cilia of fibroblasts from one of the Sensenbrenner patients and that ciliary abundance and morphology is perturbed, demonstrating the ciliary pathogenesis. Our results suggest that isolated nephronophthisis, Jeune, and Sensenbrenner syndromes are clinically overlapping disorders that can result from a similar molecular cause.

Renal Survival in Proteinase 3 and Myeloperoxidase ANCA-Associated Systemic Vasculitis

BACKGROUND AND OBJECTIVES This study evaluated predictors for patient and renal survival in patients with ANCA-associated vasculitis (AAV) with and without renal involvement. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS There were 273 consecutive AAV patients from January 1990 until December 2007 who were followed until death, loss to follow-up, or December 2010. Based on organ involvement, patients were divided into renal (n=212) and nonrenal groups (n=61). The primary end point was ESRD requiring renal replacement therapy (RRT) or renal transplantation or death. RESULTS Patient survival was significantly better in the nonrenal group compared with the renal group (hazard ratio, 0.55; 95% confidence interval, 0.33 to 0.92; P=0.02). In the renal group, renal survival was significantly worse in MPO-ANCA-positive patients (n=65) compared with PR3-ANCA-positive patients (n=138) (hazard ratio, 2.1; 95% confidence interval, 1.11 to 3.8; P=0.01). Of 48 patients who needed RRT at diagnosis, 11 patients (23%) died within 6 months and 14 patients (29%) did not regain renal function. Of all 23 patients who regained renal function after RRT, 7 patients (30%) were temporarily dialysis independent and needed dialysis later (range, 13-63 months). Five patients had a renal relapse in the 6 months before restart of RRT. Of all 203 PR3-ANCA-positive and MPO-ANCA-positive patients with renal involvement, 12 patients (6%) developed ESRD during follow-up. These patients were classified as CKD stage 4 or 5 after initial treatment and eight patients had a renal relapse before becoming dialysis dependent. CONCLUSIONS AAV patients with renal involvement who needed RRT had the worst survival probability. In multivariate analysis, the only major determinants for long-term renal survival were renal function at 6 months and renal relapses.

Effect of CYP3A4*22, CYP3A5*3, and CYP3A Combined Genotypes on Cyclosporine, Everolimus, and Tacrolimus Pharmacokinetics in Renal Transplantation

Cyclosporine, everolimus, and tacrolimus are the cornerstone of immunosuppressive therapy in renal transplantation. These drugs are characterized by narrow therapeutic windows, highly variable pharmacokinetics (PK), and metabolism by CYP3A enzymes. Recently, the decreased activity allele, CYP3A4*22, was described as a potential predictive marker for CYP3A4 activity. This study investigated the effect of CYP3A4*22, CYP3A5*3, and CYP3A combined genotypes on cyclosporine, everolimus, and tacrolimus PK in renal transplant patients. CYP3A4*22 carriers showed a significant lower clearance for cyclosporine (−15%), and a trend was observed for everolimus (−7%) and tacrolimus (−16%). Patients carrying at least one CYP3A5*1 allele had 1.5‐fold higher tacrolimus clearance compared with noncarriers; however, CYP3A5*3 appeared to be nonpredictive for everolimus and cyclosporine. CYP3A combined genotype did not significantly improve prediction of clearance compared with CYP3A5*3 or CYP3A4*22 alone. These data suggest that dose individualization of cyclosporine, everolimus, or tacrolimus therapy based on CYP3A4*22 is not indicated.

Plasma levels of soluble interleukin 2 receptor, soluble CD30, interleukin 10 and B cell activator of the tumour necrosis factor family during follow-up in vasculitis associated with proteinase 3-antineutrophil cytoplasmic antibodies: associations with disease activity and relapse

Objectives: To evaluate whether T cell activation, as reflected by levels of soluble interleukin 2 receptor (sIL2R), soluble CD30 (sCD30), IL-10 and B cell activator of the tumour necrosis factor family (BAFF) at diagnosis and during initial follow-up, is predictive for persistent or renewed antineutrophil cytoplasmic antibody (ANCA) positivity and clinical relapse in patients with vasculitis associated with proteinase 3-antineutrophil cytoplasmic antibodies (PR3-ANCA). Methods: 87 Patients with PR3-ANCA-associated vasculitis and at least 2 years of follow-up were included in the study. At diagnosis, and at 3, 6, 12, 18 and 24 months after diagnosis, cytoplasmic ANCA titres were detected by indirect immunofluorescence (IIF), and PR3-ANCA, sIL2R, sCD30, IL-10 and BAFF levels were assessed by ELISA. 31 healthy volunteers provided plasma samples for comparison. Levels of immune markers were related to ANCA positivity and relapse during follow-up. Results: Plasma levels of sIL2R, sCD30 and BAFF were higher in patients than in controls at all time points. Plasma levels of sIL2R, sCD30 and IL-10 were higher at diagnosis and relapse than during remission. At 18 months, sCD30 (p<0.001) and sIL2R levels (p = 0.01) were significantly higher in PR3-ANCA-positive patients (detected by ELISA) than in PR3-ANCA-negative patients. ANCA-positive patients detected by ELISA or IIF at 24 months had significantly higher plasma sCD30 levels (p = 0.02 and p = 0.03, respectively) than ANCA-negative patients. Conclusion: Increased T cell activation in patients with ANCA-associated vasculitis in remission during and after immunosuppressive treatment is associated with persistent or renewed ANCA positivity.

The Th1 and Th2 paradigm in ANCA-associated vasculitis.

In the pathogenesis of anti-neutrophil cytoplasm antibodies (ANCA)-associated vasculitis, T cell contribution is indicated by T cell-dependent ANCA production combined with the presence of T cells in inflammatory infiltrates. However, the exact pathogenic role of T cells in ANCA-associated vasculitis remains to be determined. The Th1/Th2 concept is useful for understanding T cell involvement in pathological processes. This review focuses on T cells and particularly the Th1/Th2 paradigm in ANCA-associated vasculitis. Most research has been done in Wegener’s granulomatosis, where a shift in T cell response, from a Th1 pattern in localized disease towards a Th0/Th2 pattern in generalized disease, appears to occur. Although less thoroughly studied, data in Churg-Strauss syndrome and microscopic polyangiitis indicate that these diseases are predominantly associated with Th2 patterns. Further studies elucidating the true nature of the polarization towards Th1 or Th2 in ANCA-associated vasculitis are clearly needed.

Plasma levels of soluble IL-2R, soluble CD30, IL-10 and BAFF during follow-up in PR3-ANCA-associated vasculitis: associations with disease activity and relapse

Objectives: To evaluate whether T cell activation, as reflected by levels of soluble interleukin 2 receptor (sIL2R), soluble CD30 (sCD30), IL-10 and B cell activator of the tumour necrosis factor family (BAFF) at diagnosis and during initial follow-up, is predictive for persistent or renewed antineutrophil cytoplasmic antibody (ANCA) positivity and clinical relapse in patients with vasculitis associated with proteinase 3-antineutrophil cytoplasmic antibodies (PR3-ANCA). Methods: 87 Patients with PR3-ANCA-associated vasculitis and at least 2 years of follow-up were included in the study. At diagnosis, and at 3, 6, 12, 18 and 24 months after diagnosis, cytoplasmic ANCA titres were detected by indirect immunofluorescence (IIF), and PR3-ANCA, sIL2R, sCD30, IL-10 and BAFF levels were assessed by ELISA. 31 healthy volunteers provided plasma samples for comparison. Levels of immune markers were related to ANCA positivity and relapse during follow-up. Results: Plasma levels of sIL2R, sCD30 and BAFF were higher in patients than in controls at all time points. Plasma levels of sIL2R, sCD30 and IL-10 were higher at diagnosis and relapse than during remission. At 18 months, sCD30 (p<0.001) and sIL2R levels (p = 0.01) were significantly higher in PR3-ANCA-positive patients (detected by ELISA) than in PR3-ANCA-negative patients. ANCA-positive patients detected by ELISA or IIF at 24 months had significantly higher plasma sCD30 levels (p = 0.02 and p = 0.03, respectively) than ANCA-negative patients. Conclusion: Increased T cell activation in patients with ANCA-associated vasculitis in remission during and after immunosuppressive treatment is associated with persistent or renewed ANCA positivity.

HDL Cholesterol Efflux Predicts Graft Failure in Renal Transplant Recipients

High-density lipoprotein (HDL) particles are involved in the protection against cardiovascular disease by promoting cholesterol efflux, in which accumulated cholesterol is removed from macrophage foam cells. We investigated whether HDL cholesterol efflux capacity is associated with cardiovascular mortality, all-cause mortality, and graft failure in a cohort of renal transplant recipients (n=495, median follow-up 7.0 years). Cholesterol efflux capacity at baseline was quantified using incubation of human macrophage foam cells with apolipoprotein B-depleted plasma. Baseline efflux capacity was not different in deceased patients and survivors (P=0.60 or P=0.50 for cardiovascular or all-cause mortality, respectively), whereas recipients developing graft failure had lower efflux capacity than those with functioning grafts (P<0.001). Kaplan-Meier analysis demonstrated a lower risk for graft failure (P=0.004) but not cardiovascular (P=0.30) or all-cause mortality (P=0.31) with increasing gender-stratified tertiles of efflux capacity. Cox regression analyses adjusted for age and gender showed that efflux capacity was not associated with cardiovascular mortality (hazard ratio [HR], 0.89; 95% confidence interval [95% CI], 0.67 to 1.19; P=0.43). Furthermore, the association between efflux capacity and all-cause mortality (HR, .79; 95% CI, 0.63 to 0.98; P=0.031) disappeared after further adjustment for potential confounders. However, efflux capacity at baseline significantly predicted graft failure (HR, 0.43; 95% CI, 0.29 to 0.64; P<0.001) independent of apolipoprotein A-I, HDL cholesterol, or creatinine clearance. In conclusion, this prospective study shows that cholesterol efflux capacity from macrophage foam cells is not associated with cardiovascular or all-cause mortality but is a strong predictor of graft failure independent of plasma HDL cholesterol levels in renal transplant recipients.

Pregnancy in women diagnosed with Antineutrophil cytoplasmic antibody–associated vasculitis: Outcome for the mother and the child

Antineutrophil cytoplasmic antibody–associated vasculitis (AAV) is infrequently seen in women of childbearing age. Only a limited number of pregnancies in women with AAV have been reported, and often they were associated with complications.

Plasmapheresis rescue therapy in progressive systemic ANCA-associated vasculitis: Single-center results of stepwise escalation of immunosuppression

Objective: We evaluated 26 patients with antineutrophil cytoplasmic autoantibody (ANCA)‐associated vasculitis (AAV) with progressive disease despite treatment with cyclophosphamide and steroids treated with additional plasmapheresis and compared outcome with 50 matched‐disease controls. Methods: Patients diagnosed with AAV and treated with cyclophosphamide from January 1990 to December 2009 (n = 272) were included when plasmapheresis was not started at diagnosis but added for progressive disease during initial standard therapy (n = 26). We selected controls equal for age, Birmingham vasculitis activity score, and creatinine at diagnosis. Primary endpoint was estimated glomerular filtration rate (eGFR) or death. Results: Plasmapheresis was added 18 days (range 5–41) after start of therapy. In 11 patients, a rise in serum creatinine >30% led to plasmapheresis; insufficient response to induction (n = 11), progressive pulmonary disease (n = 3), or progressive necrotic lesions (n = 1) were other indications.In the plasmapheresis group, six patients were in need of renal replacement therapy (RRT), and three controls. Five years after diagnosis, four patients had died in the plasmapheresis against eight controls (P = 0.94). At baseline, mean eGFR was 44 ml/min/1.73 m2 in plasmapheresis group versus 43 ml/min/1.73 m2 in controls. At start of plasmapheresis, eGFR was 26 ml/min/1.73 m2 (P = 0.003), at 6 months mean eGFR had significantly improved to 44 ml/min/1.73 m2 (P = 0.0003), comparable to eGFR in controls, 48 ml/min/1.73 m2. During long‐term follow‐up, there was no difference in renal function between the groups. Conclusion: AAV patients with progressive disease despite standard induction therapy in whom plasmapheresis was added had significant improvement in renal function and similar long‐term outcome in both renal and patient survival as matched disease controls. J. Clin. Apheresis 29:266–272, 2014.